Beneficiation of fluorite



Patented Nov. 5, 1946 2,410,770 PATENT FFiCE BENEFICIATION F FLUORITE Robert B. Booth, Springdale, and Joseph E.

Carpenter,

Greenwich, Conn., American Cyanamid Company,

N. Y., a corporationof Maine assignors to New York,

No Drawing. Application August 23, 1943, Serial No. 499,693

8 Claims.

This invention relates to'the beneflciation of non-siliceous minerals. More particularly, the invention relates to an improved'method of concentrating fluorite by froth flotation from ores containing fluorite, barite, calcite and other like non-siliceous minerals, as well as siliceous minerals.

Concentration of fluorite from fluorite-containing ores in which the remaining constituents are principally non-metallic, non-siliceous minerals constitutes an industrially important operation. Extensive installations for carrying out this operation by froth flotation are in regular use. Theoretically, the beneflciation of fluorite ores by froth flotation should be quite simple since the pure mineral itself is readily floated by the use of so-called anionic flotation reagents such as for example the fatty acids, talloel and the like as well as the various soaps thereof. Unfortunately however, the gangue constituents of many fluorite-containing ores are also readily collected by the same reagents. As a consequence, considerable work has been done to develop satisfactory methods of carrying out the operation. A number of such processes have been proposed. Some have been practically useful, others have not.

Of these proposed methods, those which have produced acceptable results have usually involved heating the ore-pulp which "is to be subjected to froth flotation. Heating the pulp apparently serves the double purpose of aiding in procuring proper dispersion of the flotation reagents and in improving their selectivity. 'In common practice, the pulp is heated to a temperature in therange of about 80-101 F. Without heating, an acceptable concentration is not only verydifllcult to obtain, but at the same time, the reagent consumption is usually excessive.

Limiting a process to elevated temperatures in this way is a serious drawback, both from the point of view of added expense and from the point of view of ease in operation. The objectionable features of the practice are particularly aggravated during cold weather, when the water supply is necessarily at a low temperature.

Despite the obvious inconveniences of heating, it has continued to be regarded as necessary for successful operation.

There remains therefore an unsatisfied de-' mand for a process of beneflciating fluorite which is not subjected to these dimcultles, i. e., one which is not particularly sensitive as to the amounts of reagents used and does not require heating-the pulp in order to obtain sucessful beneflciation.

It is, therefore, the principal object of the present invention to provide one such process. It is also an object of the present invention to provide a novel reagent combination which not only will. permit carrying out the operation without heating, but which will produce an equally good orbetter beneflciation at low temperatures than that previously obtainablewith comparable 5 amounts of 'the usual reagents, even when the latter are used in a heated pulp.

In general, the objects of the present invention are accomplished by the use of a flotation reagent comprising sulfonated petroleum hydrocarbons of the green acid type obtained in the refining of petroleum lubricating oils or salts or soaps of such acids. In addition, a suitable depressant for the calcite and the like mineralsis ordinarily used. In order to obtain optimum results, certain ores are preferably conditioned with the reagents at high solids prior to the actual those which constitute the principal reagent in carrying out the novel process of the present invention, are commercially available in a number of different forms. However, as shown, for example, in U. S. Patent 2,331,049, their principal source is as by-products from the refining of petroleum lubricating oil fractions in the course of treatment with fuming sulfuric acids or sulfuric acids, When so produced, these by-products are generally found to be salts of the sulfonated hydrocarbons. Most commonly, the metallic radical of the salt is sodium. However, salts of other metals such as the alkaline earth metals, aluminum and the like are encountered. In some cases, no attempt has been made to neutralize the acid product. Even after neutralization. free 35 sulfonates and/or sulfates are often found.

So far as the present invention is concerned, it akes little difference whether the sulfonated petroleum hydrocarbon is used per se or as a salt; whether or not the sulfur is present in a sulfate or a sulfonate group, there usually being some of both present; or whether the compounds-are used as salts of sodium, potassium, calcium, barium, aluminum and the like. Nor

need the materials be purified, since mixtures of compounds produce wholly satisfactory results.

As used in the present case, the term ,sulfonated O-Emulsifier, obtainable from L. Sonneborn' sons; Eldrol and Petrosul, obtainable from Pennsylvania Oil Products Refining (30.; Sher-- wood Reagent 407, obtainable from Sherwood Refining C0,; Ultranate #2, obtainable from Atlantic 00.; and SP-1, SP302, and

Petroleum sulfonates, or derivatives thereof,-

However, the commercially-available, sulfo- I nated petroleum hydrocarbons may be divided on a functional basis into two distinct groups. One of these is the group variously known as mahogany acids, mahogany soaps and the like. This group is characterized in that itsconstituents are generally oil-soluble but water-dispersible. Usually, but not necessarily, these compounds have a deep mahogany color when in solution which gives rise to the generic designation as mahogany" compounds.

The other group is generally, but not necessarily, characterized .by a green coloration in solution. Hence, compounds of this group are usually referred to as green-sulfonic acids or green soaps. More important than the color distinction'however, is the fact that the so-called green. compounds are characterized by being water-soluble. the two groups of compounds are by no means necessarily equivalents each to the other. Particularly is this true as in the present invention,

. when they are applied to ore dressing problems.

The instant application is primarily concerned with the use of the water-soluble petroleum sulfonates, i. e., the green sulfonic acids and salts or soaps thereof, which require considerably different treatment-than those of the mahogany? or oil-soluble type. r In general, the process of the present invention comprises the steps of reducing the ore to a size suitable for feed to a froth flotation operationi desliming the ore, if necessary; making a pulp of the ore with water: adding the reagents thereto; subjecting the pulped ore to froth flotation and flnally collecting the froth concentrate in the usual manner.

Where it is desirable to use a desliming operation, it has been found well in some cases to carry out this operation in the presence of soda ash or some equivalent alkaline material to assist in freeing the slimes. If a depressant for the gangue is to be used in the subsequent operations, it is also well to add a, small amount of the depressant during desliming. Wherev a, depressant for the gangue' minerals is to be used in carrying out the process or the present invention, quebracho was found to give excellent results. Other depressants such as dextrin, particularly yellow com Despite their other similarities overcome by the addition of an amount of a more hydrophobic material. This may be done by adding an oil in suitable quantity or by mixing some of the oil-soluble petroleum sulfonates with the water-soluble type. Any of the commercially available oils of animal, vegetable or mineral origin may be used for this purpose. Unsulfonated petroleum derivatives such as crude oil, kerosene or fuel oil are very suitable. Saponiflable oils, such as cocoanut oil, cotton seed oil and other glyceride oils may be used. Anionic materials such as the fatty acids and the lilee'also may be used, provided the gangue constituents are such as not to be floated by these materials. Talloel, in view of its low cost, is especially useful.

Amounts of these materials used will obviously vary with the particular circumstances. The

-m'ost pronounced variations in demand are ture, the pulp density, the water used. the source of the water-soluble petroleum sulfonates and the amount of slimes present, all have been found to have a direct bearing on theamount of waterphobic materials, nofixed rule applicable to all dextrin, and the alkali phosphates'and polyphosphates may be used with highly satisfactory results. In some cases no depressant is necessary.

It was also found desirable in certain cases to condition the ore-pulp with the flotation reagents .prior to the actual flotation step. Pulp densities of about -65% solids were found to give excellentresults and to be ordinarily preferable. However, if so desired, lower pulp densitieseven down to densities such as those commonly used in flotation operations per se may be used. The

invention is not necessarily limited to any particular mode of admixture, and the reagents may be addeddirectly to the flotation cell if so desired and still obtain acceptable results;

- The green p of petroleum sulfonates and/or their derivatives which are used in the present process are characterized, as noted above,.by their solubility in water. While this solubility is not always complete, it is sumciently high so that when used alone the reagent may not always produce the optimum concentration of fluorite. These green compounds appear to lack certain water-repellent. properties "which are helpful in instances can be laid down as to the amount of collecting agent required. In general, however, it has been found that amounts of water-soluble petroleum hydrocarbons ranging from about 0.1 to 5.0 lbs/ton will take care of all but the most extraordinary cases. With the ores most commonly encountered, this range can be substan-.

tially halved, since most of the ores may be readily beneflciated using an amount of reagent in the range from about 0.2 to 2.5 lbs/ton.

As has been shown, the water-soluble petroleum sulfonates have generally proved to be satisfactory when used. as the principal promoter for the fluorite minerals. However, certain external circumstances may require that the actual froth flotation operation be carried out in the presence of other substances such as oleic acid, talloel and the like which are themselves we'll known anionictype reagents. This condition may be brought about by the nature of the flow scheme employed,

the presence of these additional agents being due to other operations which are'being carried out in the same plant. 7 For example, these reagents are frequently carried along in reusing process water. It has been found that the water-soluble petroleum sulfonates are perfectly effective in the presence of these extraneous reagents. In fact, as has been noted above under some circumstances, these agents may be added deliberately in order to replace all or part of the oil normally used to overcome any difliculty which may arise due to the solubility of the sulfonated petroleum hydrocarbons. Similarly, the presence of small -Cleaner conc.per cent, CaFa amounts of the watersoluble petroleum sulfonates has been frequently found to increase the eflectiveness of these additional reagents in their are normally obtained in prior practice at high temperatures. This feature of the invention wili be more fully illustrated in connection with the following examples which are meant to be illustrative only and not by way of limitation. All

parts are by weight unless otherwise noted.

"Ibns as used in the following examples refer to short tons- ExArsrLE 1 An Illinois fluorite ore, containing chiefly fluor ite (about 72% CaFr) and limestone (about 18.5% CaCOs), was ground to minus 65 mesh and deslimed using 2 lbs/ton of soda ash and 0.1 lbJton of quebracho. The deslimed pulp was then-made up to 22% solids and conditioned for 1 minute with about 0.1 lb./ton of quebracho and vary n amounts of green acids. In different'tests the pulp was treated at diflerent temperatures. The conditioned pulp was subjected to froth flotation in a Fagergren Flotation Machine. The concentrate was cleaned once using 0.25 lb./ton of quebracho. It was found that acceptable results could be obtained using green acids in amounts varying from 0.5-2.0 lbs./ton over a temperature range of from 32-100" F. At the Table If Hydroil R. lb/ton 2.02 Gleaner cone-per cent Car's assay 0%.2'?

. Cleaner conc.per cent CaCOa assay 5.02 Cleaner conc.--per cent Cal distribution.-. 68.96 Cleaner tailing-per cent CaFr assay. 63.81 Rougher tailing-per cent Cal assay 2%.81

We claim:

lower temperatures it was found that slightly more reagent was required, that the recovery was slightly less but that the concentrate in general was of higher grade and contained less objectionable non-metallic gangue'. Illustrative results are shown in Table I.

Table I Temperature, F 86 32 LbJton-green acids 1.00 1.50 LbJton-fuel oil.. 1.00 1.50

assay 98.58 94.78 Cleaner conc.-p'er cent cacos assay Cleaner conc.per cent Cal dis- I tribution 11.33 Cleaner tailing-:per cent Calla assay -0158 Rough tailing-per cent CaFr assay 14.60 42.00

As was noted'above the presence of mahogany soap in addition to the green type oi compounds 3.96 ease ram 10 toi. 'll'his conditioned pulp was subjected to froth flotation in the Fagergren Flotation Ma= chine at room temperature as inmample 1. Illustrative results are shown in Table H.

1. A process of beneficiating fluorite-contain ing ores, which comprises subjecting an aqueous pulp of such ores to froth flotation in'the presence of from about 0.2 to 5.0 lbs/ton of ore of a collector comprising a water-soluble product selected from the group consisting of sulfonates of the green acid type obtained in the refining of petroleum lubricating oils and soaps and watersoluble salts of such sulfonates.

2. A process of beneficiating fluorite-containing ores in which a majorjportion of the gangue is comprised of non-silicious minerals, which corn prises subjecting an aqueous pulp of the ore to froth flotation in the presence of an effective t of a depressant for the non-silicious game, about 0.2 to 5.0-lbs./ton of ore of a watersoluble product selected from the group consisting of sulfonates of the' green acid type obtained in the refining of petroleum lubricating oils and soaps and water-soluble salts of'such sulfonates,

and an amount of a compatible oiling agent eflective to increase the water-repellentproperties of the, water-soluble sulfonated product. 3. A process of beneficiating fluorite-containing ores which comprises subjecting an unheated aqueous pulp of such ores to froth flotation in the presence of from about 0.2-5.0 lbsJton of ore of a collector selected from the group consist- I ing of the water-soluble sulfonates of the green acid-type obtained in the refining of petroleum lubricating oils and soaps and water soluble salts of such sulfonates.

permitted excellent beneficiation operations to be carried out using none of the oil or fatty acidwhich was found to be important when green acids alone were used. An illustration of this type of operation is shown in the following example.

Exam 2 An additional sample of the same ore treated in.

Example 1 was ground and deemed in-the same manner. Portions of the 'deslimed' ore were then felling-agent comprises an unsulfonated glyceride subjected to the conditioning operation at about 4. A process of beneflciating fluorite-containing ores in which a major portion of the gangue is comprised of non-silicious minerals which c0m-= prises subjecting an unheated aqueous pulp of the ore to froth flotation in the presence of an effective amount of a depressant for the nonsilicious gangue and about 0.2-5.0 lbs./ton of ore of a collector selected from the group cons of the water-soluble sulfonat'es 'ofthe green acid type obtained in the refining of petroleum lubrieating oils and soaps and water-soluble salts of such sulfonates. I

5. A method according to claim 2 in which the oiling-agent is present in amounts of from about 0.2 to 2.5 lbs. per ton of ore.

6. A method according to claim 2 in which the oiling-agent is an unsulfonated petroleum ,hydrocarbon. V

"7. A methodaccording to claim 2 in which the 8. A method according toclaim 2 in which the oiling-agent comprises a fatty-acid.

ROBERT E. BOOTH. 

